Hot top installation method

ABSTRACT

This invention relates to an improved method of lining the throat of an ingot mould with a so-called &#39;&#39;&#39;&#39;two-piece hot top&#39;&#39;&#39;&#39; made up of an identical pair of foldable refractory panel subassemblies, the panels of which are joined together with a fabric hinge. More specifically, the method contemplates hanging the panel subassemblies inside of the mould throat from the rim bordering the mouth thereof such that the hinged joints between panels lie in opposite corners of the mould, then spreading the panels apart until the free edges thereof engage the corresponding edges of the companion panel to form a butt joint, thereafter inserting the ends of a pair of spring wire spreaders through the butt joints and on into the mould corners remote from those occupied by the hinged joints, bending the spreaders at points alongside the midsections thereof so as to place the latter sections diagonally opposite one another in position to enter the hinged corners, and finally releasing the spreaders into position such that the midsections thereof bridge the hinged corners while cooperating with those portions bent around the free edges to bias the panels out into face-to-face contacting relation with the mould walls therebehind.

United States Patent [191 Mueller Dec. 31, 1974 HOT TOP INSTALLATIONMETHOD [75] Inventor: Ferd A. Mueller, Canon City, C010.

[73] Assignee: Colorado Refractories Corporation, Canon City, C010.

[22] Filed: Aug. 20, 1973 [21] Appl. No.: 390,081

[52] US. Cl 29/463, 29/526, 164/6, 249/137, 249/202 [51] Int. Cl B21d39/02 [58] Field of Search 29/469, 428, 463, 526; 164/6; 249/202, 137

[56] References Cited UNITED STATES PATENTS 3,362,677 1/1968 Folberth249/202 3,421,731 l/1969 Koch et a1. 249/202 X 3,732,610 5/1973 Perri29/463 3,734,454 5/ 1973 McCray 249/202 3,746,298 7/1973 Witt 249/202 X3,762,033 10/1973 McCray 29/526 X 3,802,058 4/1974 Eccleston et a1.29/428 Primary Examiner-Charlie T. Moon Attorney, Agent, orFirm-Edwards, Spangler, Wymore 8t Klaas 15 7] ABSTRACT This inventionrelates to an improved method of lining the throat of an ingot mouldwith a so-called two piece hot top" made up of an identical pair offoldable refractory panel subassemblies, the panels of which are joinedtogether with a fabric hinge. More specifically, the method contemplateshanging the panel subassemblies inside of the mould throat from the rimbordering the mouth thereof such that the hinged joints between panelslie in opposite corners of the mould, then spreading the panels apartuntil the free edges thereof engage the corresponding edges of thecompanion panel to form a butt joint, thereafter inserting the endsof apair of spring wire spreaders through the butt joints and on into themould corners remote from those occupied by the hinged joints, bendingthe spreaders at points alongside the midsections thereof so as to placethe latter sections diagonally opposite one another in position to enterthe hinged corners, and finally releasing the spreaders into positionsuch that the midsections thereof bridge the hinged corners whilecooperating with those portions bent around the free edges to bias thepanels out into face-to-face contacting relation with the mould wallstherebehind.

3 Claims, 3 Drawing Figures PATENTED DEE3 1 I974 lllu 'llil vFig 2 HOTTOP INSTALLATION METHOD Refractory linings for the neck of ingot mouldsare widely used in the steel industry to reduce piping caused by therapid cooling of the molten steel adjacent the mould walls. Thesetemporary insulating panels are commonly known in the industry as hottops, one type of which along with the method of installing same formsthe subject matter of my copending application for Letters Patent of theUnited States, Ser. No. 170,699, filed Aug. ll, 1971, now US. Pat. No.3,797,801.

These hot tops come in various shapes, designs and sizes dictated, inpart, by the type of ingot mould in which they will be used. For themost part, however, their salient features are determined as a result ofattempting to achieve ease and simplicity of installation while, at thesame time, carrying out the all important insulating function. Forinstance, one such design uses four separate wall panels and fourindividual wedgeshaped corner posts which, when properly assembledproduce an excellent insulated lining for the neck of the mould. The onewhich forms the subject matter of my copending application alreadyidentified, on the other hand, combines two of the corner posts with theadjacent panel members on both sides thereof to produce a couple offoldable subassemblies which, together with the remaining corner postsmake up a fourpiece rather than an eight-piece hot top which isconsiderably easier and less time-consuming to install. Still other hottops merely consist of refractory panels suspended in some fashioninside the neck of the mould adjacent to its walls.

Now, these various hot top designs leave much to be desired in the wayof ease and simplicity of installation although all of them functionquite well as insulators. Those with the wedge-shaped corner posts havethe advantage of a continuous insulation barrier all the way around theneck of the mould which leaves the mouth unobstructed, but they alsohave the serious disadvantages of being both difficult and slow toinstall, very fragile and easily broken especially while driving in thecorner parts, and hard to fit, particularly those used in big-end-downmoulds that have sloping trapezoidal walls.

In contrast to those hot tops that rely on the use of wedge-shapedcornerposts to hold them in place, there remains a whole group of hottops that are hung in place by some sort of wire hangers. Still others,comprise combinations of the wedge and hanger systems, the particularone forming the subject matter of my copending application being one ofthese in that wire hangers are used to suspend the foldablesubassemblies in place while the corner posts are driven therebetween.One of the most recently developed systems is of this combination typein that it uses wire hangers to suspend the panels in proper positioninside the neck of the mould, but replaces the wedge-shaped corner postswith bowed spring-wire spreaders extending across the throat of themould from approximately the midpoints on opposed panels. In theory atleast, the length of these spreaders is such that when the ends areplaced at proper points on the opposed panels, the arch therebetweenwill reach to one of the remaining panels and hold it against the mouldwall.

Of those hot tops using some sort of wire hanger system, probably one ofthe best is that which is shown in my previously identified applicationbecause, once the cornerposts are driven in place, they are primarilyrelied upon to keep the panels in proper position rather than thehangers. Even so, it suffers from many of the same deficiencies as theeight-piece hot top in that it is still somewhat difficult and slow touse although not quite as hard as the latter eight-piece unit.

The common problem shared by the wire-suspended hot tops is that whilesomewhat faster and easier to use, most of them include some structuresthat seriously encroach upon the open throat in the neck of the mouldbeneath the mouth thereof when the molten steel is introduced. if, as issometimes the case, molten steel contacts these wires and melts them,the entire hot top may collapse and become useless, especially when sucha suspension system is relied upon exclusively to hold it in place.Despite its many advantages, the previously alluded to hot top using thebowed spring wire spreaders suffers greatly from this problem becauseboth spreaders have significant sections thereof between the ends andmiddle portion well out into the throat of the mould neck were themolten steel is quite likely to contact same while it is being poured.If such should occur in a big-end-down mould, one or more of the panelsusually swing in toward one another and lose contact with the mouldwalls thus allowing the steel to flow in therebehind and cool toorapidly which is the very condition the hot top is intended toeliminate. Sometimes the hot top collapses completely and drops downinto the molten steel in the main body of the mould. Either way, the endresult is most undesirable and should be avoided, if possible, even tothe extent of using some of the more complicated systems which are notfrought with this problem.

lt has now been found in accordance with the teaching of the instantinvention that all of the desirable features of the spreader-type wiresuspension system can be realized while eliminating virtually all of itsdisadvantages by the novel, but unobvious, expedient of running thespreaders from one corner to the opposite corner along the panelsurfaces therebetween in a manner to continually bias the latter backsolidly against the corresponding mould walls. As the portions of eachspreader adjacent the ends thereof emerge from the corner and throughthe joint or crack defined between the overlapping free edges of theadjacent major and minor refractory panels and return to the insidefaces of the latter they have a pronounced tendency to dig in and holdthese edges back tight against the mould wall where the entire panelmust stay if it is to remain effective as an insulating medium. Thissame biasing action tends to spread the overlapped panels apart in thediametrically-located corners of the mould. As this happens, the hingedcorners are forced into the corners of the mould and the panelsthemselves are held tightly against the walls of the latter. Inaddition, those portions of each spreader adjacent the center sectionthereof that bridges the hinged corner are also pressing hard againstthe inside faces of the panel alongside the hinge so as to firmly biassame out against the mould walls. Thus, substantial biasing forces areat work on both ends of each panel functioning to hold them snugly inface-to-face relation against their respective mould walls so as toefficiently insulate the latter. Notwithstanding the above, thespreaders remain closely adjacent the hot top panels throughout theirlength and leave only a minimal portion exposed to the inflowing moltensteel out in the throat of the mould neck.

The improved method of the present invention, therefore, contemplateshanging each of the foldable panel subassemblies by the hinge inopposite corners of the ingot mould, swinging the major panels of eachsubassembly out into face-to-face contacting relation with thecorresponding mould wall, spreading the minor panels apart so that theirfree edges engage and hold the major panels in place, and maintainingthe panels thus positioned by bending the spring wire spreaders so as torun in opposite directions from one overlapped corner to the other pastthe hinge, the portion intermediate the ends of each spreader engagingboth panels of each panel subassembly along both free edges thereof andalso adjacent the hinged connection therebetween in a manner to biassome solidly against the mould wall therebehind. Thus, by merely runningthe spreader wires from corner-to-corner rather than from side-toside ashas been done in the past, a much improved hot top retaining systemresults.

Accordingly, it is the principal object of the present invention toprovide a novel and much improved method for installing two-piece hottops.

A second objective of the invention herein disclosed and claimed is theprovision of a method of the type aforementioned that is much fasterthan any of the methods requiring a wedge-shaped corner post to bedriven into the space between the free edges of adjacent panels.

Another object of the within described invention is to provide a hot topinstallation method that results in the spreaders being placed such thatthey lie closely adjacent the inside faces of the panels while leavingthe throat of the ingot mould neck relatively unobstructed to receivethe molten steel.

Still another objective is the provision ofa method of the classdescribed that requires no tools or special skills on the part of thepersonnel responsible for installing the hot tops.

An additional object is to provide a hot top installation method of thetype utilizing spring wire spreaders wherein the placement of thespreader ends in opposite corners of the mould insures the fact that thebend therebetween will not only engage, but tightly and uniformly biasthe panels of each subassembly solidly against the walls therebehind.

Further objects of the invention are to provide a hot top installationmethod that is easy, simple, versatile, efficient, reliable and readilyadaptable to various types and sizes of ingot moulds.

Other objects will be in part apparent and in part pointed outspecifically hereinafter in connection with the description of thedrawings that follows, and in which:

FIG. 1 is a fragmentary perspective view looking down into the throat ofan ingot mould through the mouth thereof where the hot top, wire hangersand spreaders therefor are shown in place, substantial portions havingbeen broken away and shown in section to more clearly reveal theconstruction;

FIG. 2 is a top plan view of the completed installation; and,

FIG. 3 is a greatly enlarged fragmentary section showing theconstruction in the corner where the major and minor panels overlap.

Referring next to the drawings for a detailed description of the presentinvention and, initially to FIGS. 1 and 2 for this purpose, referencenumeral 10 has been chosen to represent in a general way a conventionalingot mould, only the'neck 12 of which has been shown. The inside of theneck will, for present purposes, be referred to as the throat 14 thereofand the upwardly-facing entrance thereto through which the molten steelis poured, the mouth 16. The particular neck illustrated in FIG. 1 islike that found on a socalled big-end-down" ingot mould and the methodof the present invention will be described in connection with installinga two-piece hot top that has been broadly referred to by referencenumeral 18 in the throat of the latter; however, it is to be clearlyunderstood that this method is, by no means, restricted to such a useand it can, without modification, be practiced as a method of installingappropriatly-designed hot tops in other types and sizes of ingot moulds.

The method is specifically designed for use with what will henceforth bedenominated as a two-piece hot top of the type having an identical pairof foldable refractory panel subassemblies 20 hinged intermediate theends thereof by a fabric sheet 22 permanently fastened to their insidefaces 24 in position to bridge the joint therebetween and define hinge26. Ideally, this fabric sheet is molded integral with the panelsthemselves and is impregnated with a refractory material capable ofwithstanding the temperature of the molten steel although, obviously,other types of hinged connections can be used and the method forming thesubject matter hereof will work just as well. i

It will also be noted that, in the particular form shown, each of thepanel subassemblies 20 has what will be denominated here as a majorpanel 28 and a minor panel 30, the only difference therebetween being intheir respective widths. The major panels 28 are both of a length toreach all the way from one corner of the mould to an adjacent cornerthereof, whereas, the minor panels are narrower by an amountapproximating the thickness of a single panel. As so constructed, theabutting free edges of the major and minor panels of the two panelsubassemblies will occupy an overlapped relation to one another in thecorners remote from the hinges as clearly revealed in all three figures.The advantages of such a construction are two-fold, namely, it providesbetter insulation in the corners and the minor panel constitutes astructure capable of temporarily holding the major panel solidly inplace against the mould wall when swung outwardly thereagainst ingate-like fashion. This overlapped condition cannot be relied upon tohold the hot top in place while the ingot is being poured but it is,nevertheless, helpful as a means for doing so until the spreaders 32 canbe installed. Here again, while the use ofa two-piece hot top havingmajor and minor panels in each panel subassembly has certain advantagesboth in terms of ultimate function and ease of installation, the methoddefined herein is equally well suited for use with two-piece hot topshaving equal-width panels in each panel subassembly assuming, of course,that the cross-section of the mould throat is square rather thanrectangular.

The hangers 34 by means of which the hot top is suspended within thethroat of the ingot mould are revealed most clearly in FIGS. 1 and 2 towhich continued reference will be made. They consist of nothing morethan inverted generally U-shaped wires having legs 36 and 38 ofdifferent lengths, both of which terminate at their free ends inupturned hooks 40 turned in wardly toward one another.

The first step in the method is to hang the panel subassemblies inopposite corners of the ingot mould. This is accomplished with hangers34 as follows. Initially, a choice must be made as to whether the hottop is to hang high or low in the throat of the mould and the hanger legis selected accordingly. Ordinarily, the appropriate hanger leg will berun down along the inside of the hinged joint and hook 40 will be hookedbeneath hinge 26 in the manner most clearly shown in FIG. 1 before thehanger itself is hung over the rim 42 of the mould in one of its fourcorners. Single-hook hangers can, of course, be used in place of thedouble-hook ones shown as can other types and styles of hangers capableof suspending the hot top subassemblies in the mould throat. Theparticular hangers shown have the advantage of being well out of the wayof the molten steel as it enters the mouth of the mould while remainingsimple and versatile due to their reversability.

Now, with the panel subassemblies being in place in opposite corners ofthe mould, the normal tendency will, of course, be to have the hingedlyinterconnected panels thereof fold in toward one another, especially ina big-end-down mould where the throat widens from the mouth down and thehangers tilt in toward one another at the top. The next step, then, isto spread the major panels 28 apart until they lie flush against theirrespective mould walls, whereupon, the minor panels 30 can be swung outin gate-like fashion so that the free edges 44 thereof engage the insidefaces of the major panels in overlapping relation so as to temporarilyhold the latter in place as shown. In actual practice, the subassembliesare placed in the throat of the mould such that the minor panels of eachsuch subassembly are folded inside the major panels of the othersubassembly. Then, by merely swinging the minor panels out, the freeedges 44 thereof will slide along the inside faces of the major panelsof the other subassembly and push them out against the mould walls. Uponcompletion of this operation when the free edges of the minor panelsreach the corresponding edges of the major panels, all of the free edgeswill be in the corners of the mould and the minor panels will also lieessentially flush against the mould walls therebehind.

With the panels thus temporarily held in place, the time has come tosecure them there by installing the spreaders 32. In accordance with theprior art method, the ends 46 of each spreader would be inserted intothe opposite panels as close to the midpoint thereof as possible andthen the center section of the wire would be pulled in and releasedagainst the central area of one of the panels therebetween. The problemwith this method is that if the points are inserted too far from themiddle panel, the bend will never reach the latter or, if it does, saidpanel will be only weakly biased against the mould wall therebehind.Conversely, if the spreader ends are inserted too close to the middlepanel, it may not be possible to bend the wire enough to bring themidsection thereof into position where it will pass in front of thelatter thus leaving it loose. Furthermore, even when properly installed,the spreaders make essentially three-point contact at the midpoints ofthe three panels thus leaving the sections intermediate the midpoint andthe ends well out in the throat of the mould where the molten steel ismost likely to contact same and melt the wire. If this should occur, thebias holding the panels in insulating relation to the mould walls islost and the molten steel will rise up therebehind and become chilled sothat the primary function to be served by the hot top is lost. Notinfrequently, the loss of the spreaders will allow one, if not both ofthe panel subassemblies to come loose from its hanger and fall down intothe main body of the ingot being formed as the molten steel contacts itspartially folded leaves or panels.

All of the aforementioned difficulties are eliminated in accordance withthe teaching of the instant invention wherein the spreaders 32 areinstalled as shown in FIGS. 1, 2 and 3 to which detailed reference willnow be made. Instead of having to locate the midpoints of oppositepanels as has been the situation up to now, the free ends of eachspreader are merely passed through the joint 48 defined by theoverlapping panel edges and into opposite corners 50 of the mould. Allguess work is eliminated and, in fact, the spreader ends willautomatically seek and seat in these opposite corners if, perchance, onewere to miss the joint 48 a little bit. It is not necessary that thespreader ends be located halfway up the joint between panels although,preferably, they should be positioned nearer the middle than either thetop or bottom. While the location of the hot top in the low or highposition and the placement of the spreaders relative to the top andbottom thereof will have some effect on the tension developed in thewires and the biasing force exerted upon the panels in those mouldshaving tapered throats, the overall effect will be slight and of noconsequence.

Now, in contrast to the prior art method of installing spreaders, eachspreader bridges only the two panels of g the same subassembly ratherthan three. As indicated most clearly by the arrow in FIG. 1, theportions of each spreader 52 alongside the midsection 54 thereof aregrasped and bowed inwardly to bring said midsection inside the hingedcorner 56, whereupon, it is dropped down to a level essentially coplanarwith the ends and released. As this occurs, a point on each of thespreaders immediately adjacent the opposite ends thereof will pivotaround the fulcrumforming free edges of the panels of one panelsubassembly thus forcing them solidly against the form wall therebehind,while, at the same time causing the ends projecting therebeyond to digtheir way into the relatively soft overlapped free edge of the panelterminating in the same joint.

From the corners of the panels, the wires may bow slightly inward awayfrom inside surfaces of the latter only to return at a point adjacentthe hinged corner as revealed most clearly in FIG. 2, however, thesespreader wires are usually sufficiently stiff to remain quite close tothe panel wall therebehind for nearly the full length thereof and, inmany instances, force their way into the panel surfaces so as to remainin contact therewith all the way up to near the hinged corner. Onceagain, the midsection 54 of the wire leaves the panel surfaces to bridgethe hinge therebetween with a bow or bend that still leaves it well outof the path of the incoming molten steel. The biasing force exerted uponeach panel is essentially uniform and all are biased firmly against themould walls therebehind so as to maintain a flush insulating relationthereto.

Of course, each of the two spreader wires extends in a directionopposite to the other around the hinged corner of the mould from theshared or common joints 48 between the lapped ends of the two panelsubassemblies. In so doing, each spreader wire cooperates with itsparticular panel subassembly to bias the other panel subassembly tightlyinto the corner in which its hinge is located. This occurs because thespreader wires employ the free edges of their own panels as fulcrumsaround which they bend while the ends beyond said bends engage the freeedges of the other panel subassembly and urge them toward the hingedcorner, all of which is revealed in FIG. 3. This particular cooperativerelationship is particularly evident in two-piece hot tops of the typeshown having major and minor panels in each panel subassembly although,it may occur to a lesser extent in those hot tops having the panelssized to meet and mate in the corners remote from the hinges in the sameway they do at the hinges. Note, also, that as the spreader ends diginto the panel edges and seat in the corners of the mould, they definehot top supporting structures capable of maintaining the position of thelatter in the mould throat even without the hangers.

What is claimed is:

l. The method of installing a two-piece hot top of the type consistingof a pair of identical foldable refractory panel subassemblies withinthe generally rectangular throat in the hollow neck of an ingot mouldwhich comprises the steps of: placing the foldable joints between panelsof the respective panel subassemblies in opposite corners of the mouldthroat, suspending the subassemblies thus positioned from the rim of theneck bordering the mouth into the throat thereof, unfolding the panelsof each panel subassembly to the point where the free edges of oneengage those of the other to define butt joints therebetween, insertingthe ends of a pair of spring wire spreaders through the butt joints thusformed and into those corners of the mould throat remote from the onesoccupied by the foldable joints, independently bending those portions ofeach spreader adjacent its midsection inwardly so as to locate thelatter sections diagonally opposite one another in position to enter thefoldable joints, and releasing the spreaders into positions suchthat-the midsections thereof engage the inside panel faces at spacedpoints on opposite sides of the foldable joint while those portionsadjacent the spreader ends pivot around the free edges of theirrespective panel subassemblies and cooperate with said midsectionsthereof to bias the panels outward into tight face-to-face contact withthe mould walls therebehind.

2. The method as set forth in claim 1 which includes the step of usingthe free edge of one panel of each panel subassembly to engage and holdthe adjacent panel of the other panel subassembly out against the mouldwall therebehind while the spreaders are being installed.

3. The method as set forth in claim 1 in which the panel subassembliesare suspended from the rim of the mould neck by backing same over thelatter and underneath the hinged joint.

1. The method of installing a two-piece hOt top of the type consistingof a pair of identical foldable refractory panel subassemblies withinthe generally rectangular throat in the hollow neck of an ingot mouldwhich comprises the steps of: placing the foldable joints between panelsof the respective panel subassemblies in opposite corners of the mouldthroat, suspending the subassemblies thus positioned from the rim of theneck bordering the mouth into the throat thereof, unfolding the panelsof each panel subassembly to the point where the free edges of oneengage those of the other to define butt joints therebetween, insertingthe ends of a pair of spring wire spreaders through the butt joints thusformed and into those corners of the mould throat remote from the onesoccupied by the foldable joints, independently bending those portions ofeach spreader adjacent its midsection inwardly so as to locate thelatter sections diagonally opposite one another in position to enter thefoldable joints, and releasing the spreaders into positions such thatthe midsections thereof engage the inside panel faces at spaced pointson opposite sides of the foldable joint while those portions adjacentthe spreader ends pivot around the free edges of their respective panelsubassemblies and cooperate with said midsections thereof to bias thepanels outward into tight face-to-face contact with the mould wallstherebehind.
 2. The method as set forth in claim 1 which includes thestep of using the free edge of one panel of each panel subassembly toengage and hold the adjacent panel of the other panel subassembly outagainst the mould wall therebehind while the spreaders are beinginstalled.
 3. The method as set forth in claim 1 in which the panelsubassemblies are suspended from the rim of the mould neck by backingsame over the latter and underneath the hinged joint.